TW201435912A - Thermal monitor for an extreme ultraviolet light source - Google Patents

Abstract

A first temperature distribution that represents a temperature of an element adjacent to and distinct from a first optical element that is positioned to receive an amplified light beam is accessed. The accessed first temperature distribution is analyzed to determine a temperature metric associated with the element, the determined temperature metric is compared to a baseline temperature metric, and an adjustment to position of the amplified light beam relative to the first optical element is determined based on the comparison.

Description

Thermal monitor for extreme ultraviolet light sources

This disclosure relates to a thermal monitor for one of the extreme ultraviolet (EUV) light sources.

Extreme ultraviolet (EUV) light, for example, having a wavelength of about 50 nm or less (sometimes referred to as soft x-rays), and including electromagnetic radiation having a wavelength of about 13.5 nm, can be used for light. The lithography process produces very small topography in a matrix such as a germanium wafer.

Methods of producing EUV light include, but are not necessarily limited to, converting materials having elements such as germanium, lithium or tin having radiation in the EUV range to a plasma state. In such a method, commonly referred to as laser-generated plasma (LPP), the desired plasma can be generated by illuminating the target with an amplified beam of light that can be referred to as a driven laser, such as a target. Material droplets, streams, or clusters. For such procedures, the plasma is typically generated in a closed container, such as a vacuum chamber, and monitored using a variety of types of metrology equipment.

In a generalized aspect, a method for adjusting a position of an amplified beam relative to a first optical element in an extreme ultraviolet (EUV) source includes taking a temperature indicative of a temperature adjacent to the first optical element and a component thereof A temperature distribution. This first optical element is arranged to receive an amplified beam. The method also includes analyzing the first temperature profile taken to determine a temperature metric associated with the component, comparing the determined temperature metric to a baseline temperature metric, and determining the position of the amplified beam relative to the result of the comparison Adjustment of the first optical component.

A present case may include one or more of the following features. Can produce a representation pair An indicator of the determined adjustment of the position of the amplified beam. The indicator can include an input for an actuator for mechanical coupling to the second optical element, the second optical element can include an active region configured to receive the amplified beam, and the input to the actuator can be sufficient to cause the actuator The active area is moved in at least one direction. These inputs can be provided to the actuator. After providing such input to the actuator, a second temperature profile of the component adjacent the first optical component can be taken, the second temperature profile can be analyzed to determine a temperature metric, and the temperature metric can be compared to the first One or more of the temperature distribution or baseline temperature metrics are compared.

This indicator may also include a third light for coupling into the EUV source The input to a second actuator of the component is such that the input to the second actuator is sufficient for the second actuator to move the third optical component in at least one direction. The active area of the second optical element can include a mirror having a reflective portion that receives the amplified beam, and when moved, the reflective portion changes the position of the magnified beam relative to the first optical element.

The first temperature distribution can include a element adjacent to the first optical element The temperature of a portion of the part, the temperature of which is measured at least two different times. The first temperature distribution can include a plurality of components adjacent to the first optical component The temperature of the part. The temperature of each of the plurality of sections can be measured at least two different times. The first temperature profile can include data indicative of temperature measurements received by the thermal sensor, the thermal sensors being mechanically coupled to components adjacent to the first optical component. The first temperature profile can include a plurality of temperatures measured by the component at different times, and the temperature metric can include a variance of the plurality of temperatures, an average of the plurality of temperatures, or at least between the plurality of temperatures One or more of the rate of change.

The first optical element can be used to amplify the beam The mirror, and the element adjacent to the converging lens, can be a mirror cover.

The first temperature distribution can include the component at a particular time A plurality of temperatures are measured at different locations, and the temperature metric can include a spatial variance of the plurality of temperatures. The first temperature profile can also include a plurality of temperatures of the component measured at different locations on the component adjacent the first optical component. The temperature metric can also include a spatial variance of the plurality of temperatures measured at different locations on the component adjacent the first optical component. The temperature metric can include a value indicative of one of the measured temperatures of the element adjacent the first optical element as a function of time, and comparing the temperature metric to the baseline temperature metric can include comparing the value to a threshold.

In another generalized aspect, a system includes a thermal sensor, The thermal sensor assembly is configured to mechanically couple to an element adjacent to the first optical element of the amplified beam of the extreme ultraviolet (EUV) source, measure the temperature of the element, and produce an index of the measured temperature. The system also includes a controller including one or more electronic processors coupled to a non-transitory computer readable medium, the computer readable medium storage including one or more electronic processes The software executed by the device, when executed, causes the one or more electronic processors to receive an index of the generated measured temperature, and generate an output signal according to the generated index of the measured temperature, the output The signal is sufficient to cause the actuator to move a second optical component that receives the amplified beam and adjust a position of the amplified beam relative to the first optical component.

A present case may include one or more of the following features. First optical component It may be a lens through which the light beam is amplified, the element adjacent to the lens may be a mirror cover adjacent to the lens, and the thermal sensor may be assembled to be mounted to the lens cover. The thermal sensor can include one or more of a thermocouple, a thermal resistor, or a fiber-based thermal sensor. This first optical element can be one of a power amplifier output window, a final focus rotating mirror, or a spatial filter aperture. The thermal sensor can include a plurality of thermal sensors, the first optical component can include one or more optical components downstream of the lens that focuses the amplified beam, and each of the one or more optical components can be coupled to a thermal Sensor. The one or more optical elements can be a mirror body.

The instructions may also include instructions to provide an output signal to the actuator, and This actuator can be assembled to couple to the second optical element. The instructions may also include instructions that, when executed, cause the controller to: take a first temperature profile that is based on an index of the measured temperature of the component from the thermal sensor; The temperature profile determines a temperature metric associated with the component; the determined temperature metric is compared to a baseline temperature profile; and the adjustment of one of the parameters of the amplified beam is determined based on the result of the comparison.

In another generalized aspect, a system includes a first optical component that receives an amplified beam of an extreme ultraviolet (EUV) source, and is adjacent and respectively An element of the first optical component. The system also includes a thermal system coupled to the component adjacent the first optical component, and the thermal system includes one or more temperature sensors each associated with a different portion of the component, the one or more The temperature sensor is configured to generate an index of the measured temperature of the associated portion of the component; and an actuating system coupled to a second optical component that, when moved, causes an amplification of the beam Corresponding to move. The system also includes a control system coupled to the output of the thermal system and one or more inputs of the actuation system, and configured to generate an input for actuation of the system based on the generated index of measured temperature An output signal sufficient to cause the actuator to move the second optical element and to adjust a position of the amplified beam relative to the first optical element.

A current example of any of the above techniques may include a method, a A program, a device, a kit for retrofitting an existing EUV source, or a device. One or more of the details of the present invention will be described in the following figures and the following description. Other features will be apparent from the description and drawings and from the scope of the claims.

100‧‧‧Light source

105, 610‧‧‧ Target location

107‧‧‧Internal

110‧‧‧Amplified beam

114‧‧‧Target mixture

115‧‧‧Laser system

120, 240, 615‧ ‧ beam transmission system

122, 620‧ ‧ focus assembly

124‧‧‧Metric system

125‧‧‧Target delivery system

127‧‧‧ target supply device

130‧‧‧Case/vacuum container

135‧‧‧ concentrator

140, 197‧‧‧ aperture

145‧‧‧ intermediate position

150‧‧‧ mask

155‧‧‧Master controller

156‧‧‧Droplet position detection feedback system

157‧‧‧Laser Control System

158‧‧‧ Beam Control System

160‧‧‧ Imager

165‧‧‧Light source detector

175‧‧‧Guided laser

180, 605‧‧‧ drive laser system

181, 182, 183‧ ‧ amplifiers

184, 191, 665 ‧ ‧ rays

185, 190, 194‧‧‧ output windows

186, 188‧‧‧ bending mirror

187‧‧‧ Space filter

189, 193‧‧‧ input window

192‧‧‧Folding mirror

195‧‧‧Output beam

210‧‧‧Final Focus Assembly / Final Focus Lens Assembly

212‧‧‧Lens Holder

214‧‧‧Guide mirror

215‧‧‧reflection

216, 221‧‧ ‧ actuator

217‧‧‧Retainer

218‧‧‧ final focus lens

220‧‧‧Support frame

228A~228D‧‧‧Temperature Sensor

Around 234‧‧

235, 236‧‧‧

237‧‧‧ inner surface

238‧‧‧ outer surface

241‧‧‧EUV monitoring module

242‧‧‧guide module

243‧‧‧ position

244‧‧‧ Center

302~308‧‧‧ Time Series

600‧‧‧beam delivery system

625‧‧‧Amplified beam

630, 632, 638‧‧ ‧ Mirror / optical components

634‧‧‧Guiding optics/optical components

640‧‧‧beam extension system

650‧‧ ‧ Mirror body

655‧‧‧ Converging lens

660‧‧‧Metric system

670‧‧‧Aligning the laser

675‧‧‧Detection device

680‧‧‧Diagnostic beam

700‧‧‧ system

710‧‧‧ Thermal Sensor

712‧‧‧Sensor

714, 744‧‧‧ coupling parts

716, 736, 746‧‧‧Input/Output Interface/I/O Interface

718‧‧‧Power Module

720‧‧‧Monitored components

722‧‧‧High power optical components

730‧‧‧ Controller

732‧‧‧ processor

734‧‧‧Electronic storage

740‧‧‧ actuation system

742‧‧‧Activity agency

750‧‧‧guide elements

752‧‧‧Action area

800‧‧‧ procedures

810~840‧‧‧Steps

Figure 1A is a block diagram of a laser generated plasma extreme ultraviolet light source.

Figure 1B is a block diagram of an exemplary driven laser system that can be used in the light source of Figure 1A.

Fig. 2A is a side elevational view showing an example of the light source of Fig. 1A.

Figure 2B is a front view of one of the mirror covers of Figure 2A taken along line 2B-2B view.

Figures 3A and 3B are examples of measured temperatures as a function of time.

4A is a side elevational view of an exemplary embodiment of the light source of FIG. 2A having a misaligned magnified beam.

Figure 4B is a front elevational view of the final focus lens of Figure 4A.

Figure 5A is a side elevational view of an exemplary embodiment of the light source of Figure 2A having an aligned magnified beam.

Figure 5B is a front elevational view of the final focus lens of Figure 5A.

Figure 6 is an illustration of an example beam delivery system.

Figure 7 is a block diagram of an exemplary system for aligning an amplified beam.

Figure 8 is an exemplary procedure for aligning an amplified beam.

A thermal monitor for one of the extreme ultraviolet (EUV) sources is disclosed. The thermal monitor determines the temperature of the components adjacent to and respectively receiving the optical elements of one of the amplified beams. The magnified beam is directed toward the stream of target droplets, and when the magnified beam interacts with a target droplet, the target droplet is converted to a plasma state and emits EUV light.

The thermal monitor can enhance the performance of the EUV source by providing a more accurate positioning of the magnifying beam relative to the optical element that reflects or refracts the beam. Since the EUV light system is generated by irradiating a target droplet with an enlarged beam, aligning the amplified beam to focus the beam on the target position through which the target droplet passes, can provide concentrated energy to the fine droplet, and promote the fine droplet It is possible to convert into Plasma, thus increasing the amount of EUV light produced and improving the overall performance of the EUV source. Furthermore, maintaining the alignment and quality of the amplified beam enhances the stability of the EUV power generated by the source. In addition, monitoring the spatial temperature distribution and the intensity symmetry on the components receiving the amplified beam also allows for compensation for errors caused by thermal drift.

As described below, monitoring is adjacent to receiving one of the amplified beams The temperature of an element of an optical component, such as a lens or mirror, such as a mirror cover, can improve the alignment of the magnified beam. Direct and indirect radiation to an element heats the element and produces a measurable change in the temperature of the element. The amount of radiation from the amplified beam that is absorbed or exposed by the component depends on the quality of the beam alignment. For example, if the magnified beam is properly collimated and aligned with respect to a lens, the intensity distribution of the beam on the lens will be substantially spatially and/or temporally uniform. When the magnified beam is properly aimed, the intensity distribution is symmetric and lies in the center of the lens and the element adjacent the lens. Since the intensity distribution on the lens is uniform, the heating effect on the lens and the element adjacent to the lens is also uniform; in addition, the intensity distribution of the beam reflected from the material droplets is collimated and uniform.

Conversely, if the amplified beam is misaligned, the amplified beam on the lens The intensity distribution and the intensity distribution of the reflected beam are not uniform. For example, in the event of misalignment, the magnified beam may eccentrically (off-center) through the lens and may have an asymmetrical intensity distribution, which may cause some portions of the lens and/or adjacent elements to heat more than others. This uneven heating can result in localized hot spots that can cause thermal damage to the lens and/or adjacent components. In addition, such hot spots may cause optical effects such as thermal lenses in the lens, which may The focal length of the lens is changed due to the change in the refractive index and the performance of the light source is lowered. Optical effects refer to those effects that alter the optical properties of the lens on the lens. Furthermore, when misaligned, the magnified beam may eccentrically illuminate the scope and strike a non-reflective element or strike a non-transmissive element adjacent to an aperture or lens. In this two example, the amplified beam may become asymmetrical and cause adjacent elements to have an uneven intensity distribution.

In other words, inaccurate alignment of the amplified beam may result in the lens The temperature distribution is not uniform in time and/or space. Thus, the temperature of portions of a thermally conductive element or component adjacent the lens may also be non-uniform. Therefore, the measurement of the uneven temperature distribution on adjacent components can be an indicator of the misalignment of the amplified beam. Furthermore, by characterizing (ie, presenting) the temperature distribution on adjacent components, the amount of misalignment can be determined and used to adjust the position of the optical element that directs the amplified beam toward the target droplet. To adjust or correct the alignment of the amplified beam.

In addition, the characterization of the temperature distribution on adjacent components allows for heat Compensation for performance changes caused by drift. The optical components in an EUV source may expand in size when exposed to heat. For example, a mirror body or a body that holds the mirror body may expand due to rapid heating and/or heating for a period of time. This additional heating may occur as the duty cycle of the amplified beam increases. Thermal expansion may result in small changes in the position of the mirror body, causing a pointing drift, which is a change in the direction of travel of the light reflected from the mirror body. Pointing drift may cause the amplified beam to be not centered in the optical element downstream of the mirror. Pointing drift can also result in an asymmetric intensity distribution on the downstream optical components.

The thermal monitors discussed below can also be used to zoom in by decision Whether the beam is asymmetrically placed on the optical element, and if the beam is asymmetrically positioned, the amplified beam is repositioned such that the beam is centered at the center of the optical element with a symmetric intensity distribution to compensate for the pointing drift.

Accordingly, the thermal monitoring technique described below can be improved by amplifying light. Beam alignment and compensation for thermal drift to improve the performance of the EUV source. Below, the EUV source will be discussed before discussing the thermal monitor in more detail.

Referring to FIG. 1A, an LPP EUV light source 100 is used in a target Position 105 illuminates the target mixture 114 with an amplified beam 110 traveling along a beam path toward a target mixture 114. The target position 105, also referred to as the illumination position, is positioned in the interior 107 of the vacuum chamber 130. When the amplified beam 110 illuminates the target mixture 114, a target within the target mixture 114 is converted to a plasma state having elements of radiation in the EUV range. The resulting plasma has certain characteristics depending on the target composition within the target mixture 114. These characteristics may include the wavelength of the EUV light produced by the plasma and the type and amount of debris released from the plasma.

Light source 100 also includes a target delivery system 125 that transmits, controls, and directs liquid droplets, liquid streams, solid particles or clusters, solid particles contained within liquid droplets, or contained within a liquid stream. Target mixture 114 in the form of solid particles. This target mixture 114 includes targets such as, for example, water, tin, lithium, cesium or any material that has radiation in the EUV range when converted to a plasma state. For example, using pure elemental tin, tin (of Sn); e.g. SnBr _4, SnBr _2, SnH _4, a tin compound; e.g. tin-gallium alloys, indium-tin alloy, tin alloy, tin-indium-gallium alloys, or combinations of these alloys. Target mixture 114 may also include impurities such as non-target particles. Therefore, in the absence of impurities, the target mixture 114 is made only of the target. The target mixture 114 is delivered by the target delivery system 125 into the interior 107 of the chamber 130 and to the target location 105.

Light source 100 includes a drive laser system 115 due to a laser system Amplifying inversion of one or more of the gain media produces an amplified beam 110. The light source 100 includes a beam delivery system between the laser system 115 and the target location 105. The beam delivery system includes a beam delivery system 120 and a focus assembly 122. This beam delivery system 120 receives the amplified beam 110 from the laser system 115 and directs and modifies the amplified beam 110 as needed, and outputs the amplified beam 110 to the focus assembly 122. This focus assembly 122 receives the amplified beam 110 and focuses the beam 110 at the target position 105.

In some embodiments, the laser system 115 can include One or more primary amplifiers and, in some cases, one or more optical amplifiers, lasers, and/or luminaires that provide one or more pre-pulses. Each optical amplifier includes a gain medium, an excitation source, and an internal optical mechanism that optically amplifies a desired wavelength at a high gain. This optical amplifier may or may not have a laser or other feedback device that forms a laser cavity. Thus, the laser system 115 produces an amplified beam 110 due to cluster switching in the gain medium of the laser amplifier, even without a laser cavity. In addition, if a laser cavity provides sufficient feedback to the laser system 115, the laser system 115 can produce an amplified beam 110 of the coherent laser. The term "magnifying beam" encompasses one or more of the following rays: light from the laser system 115 that is only amplified but not necessarily a coherent laser oscillation, and light that is amplified and also is a coherent laser oscillation.

The optical amplifier in laser system 115 can include a fill gas as a gain medium that includes CO ₂ and can illuminate light having a wavelength between about 9100 and about 11000 nm, and particularly at about 10600 nm. Or a gain equal to 1000 to amplify. Suitable amplifiers and lasers for use in the laser system 115 can include a pulsed laser device, such as a pulsed gas discharge CO ₂ laser device that produces radiation at about 9300 nm or about 10600 nm, for example, by DC or RF excitation. It operates at a relatively high power of, for example, 10 kW or higher, and a high pulse repetition rate of, for example, 50 kHz or higher. The optical amplifier in the laser system 115 can also include a cooling system, such as water used by the laser system 115 to operate at higher power.

FIG. 1B shows a block diagram of an example driven laser system 180. this The drive laser system 180 can be used as a drive laser system 115 in the light source 100. This drive laser system 180 includes three power amplifiers 181, 182, and 183. Either or all of power amplifiers 181, 182, and 183 may include internal optical components (not shown).

Light 184 is emitted from power amplifier 181 through an output window 185 And reflected from a curved mirror 186. After reflection, light 184 passing through a spatial filter 187 is reflected by a curved mirror 188 and passed through an input window 189 into power amplifier 182. Light ray 184 is amplified in power amplifier 182 and re-exported power amplifier 182 as light 191 through an output window 190. Light ray 191 is directed toward amplifier 183 by folding mirror 192 and into amplifier 183 through an input window 193. Amplifier 183 amplifies light 191 and directs light 191 through an output window 194 to amplifier 193 as an output beam 195. A folding mirror 196 directs the output beam 195 upward (from the page) and toward the beam delivery system 120.

The space filter 187 defines an aperture 197, which may for example have A circle of diameter between 2.2 mm and 3 mm. The curved mirrors 186 and 188 can be, for example, off-axis parabolic mirrors having focal lengths of 1.7 m and 2.3 m, respectively. This spatial filter 187 can be positioned such that the aperture 197 coincides with the focus of one of the drive laser systems 180.

Referring again to FIG. 1A, the light source 100 includes an aperture 140. The amplified beam 110 passes through and reaches a concentrating mirror 135 at the target location 105. The concentrating mirror 135 can be, for example, an elliptical mirror having a primary focus at the target position 105 and a secondary focus (also referred to as an intermediate focus) at the intermediate position 145, wherein the EUV light can be output from the light source 100 and can be input, for example, an integrated body. Circuit lithography tool (not shown). The light source 100 can also include an open ended hollow conical mask 150 (eg, a gas cone) that tapers from the concentrating mirror 135 toward the target location 105 to reduce plasma while allowing the amplified beam 110 to reach the target location 105. The resulting debris enters the number of focus assemblies 122 and/or beam delivery systems 120. For this purpose, the airflow directed towards the target location 105 can be provided in the mask.

The light source 100 can also include a main controller 155 connected to the fine droplets Position detection feedback system 156, laser control system 157, and beam control system 158. The light source 100 can also include one or more target or fine droplet imagers 160 that provide an output indicative of, for example, a droplet position relative to the target location 105, and provide this output to the droplet position detection feedback system 156. For example, the position and orbit of the fine droplets can be calculated, and from the fine droplet positions and the tracks, the fine droplet position error can be calculated by one fine drop or one fine drop or evenly. This fine drop position detection feedback system 156 thus provides fine drop position error as the primary control The input of the device 155. The main controller 155 can thus provide a laser position, direction, and timing correction signal, such as a laser control system 157 and/or a beam control system 158 that can be used, for example, to control a laser timing circuit to control the beam. The amplified beam position and shaping of transmission system 120 changes the position of the beam focus and/or focus power within chamber 130.

Target delivery system 125 includes a target delivery control system 126 that The operation may be responsive to signals from the main controller 155, such as correcting the release point of the droplets as they are released by the target supply 127 to correct for errors in the fine droplets reaching the desired target position 105.

Additionally, light source 100 can include measuring one or more EUV light parameters a light source detector 165, such as but not limited to pulse energy, energy distribution as a function of wavelength, energy in a particular wavelength band, energy outside a particular wavelength band, and EUV intensity and/or average The angular distribution of power. Light source detector 165 generates a feedback signal for use by main controller 155. This feedback signal may, for example, indicate errors in the timing of the laser pulse and the parameters of the focus to properly intercept the droplets at the correct point and time for efficient and efficient EUV light production.

The light source 100 can also include a guiding laser 175 for aligning light The plurality of sections of source 100 or auxiliary guides the amplified beam 110 to the target location 105. With respect to guiding the laser 175, the light source 100 includes a metrology system 124 disposed within the focus assembly 122 to partially sample one of the light from the pilot laser 175 and the amplified beam 110. In other embodiments, the metrology system 124 is disposed within the beam delivery system 120. The metrology system 124 can include an optical component that samples or redirects a subset of the light that is tolerated Made of any material that directs the laser beam and amplifies the power of the beam 110. Since the main controller 155 analyzes the sampled light from the pilot laser 175 and uses this information to adjust the components within the focus assembly 122 through the beam control system 158, the metrology system 124 and the main controller 155 form a beam analysis system.

Therefore, in summary, the light source 100 produces an amplified beam 110, It is directed along the beam path to illuminate the target mixture 114 at the target location 105 to convert the target within the mixture 114 into a plasma that emits light in the EUV range. This amplified beam 110 operates at a particular wavelength (also referred to as the source wavelength) that is determined based on the design and characteristics of the laser system 115. In addition, the amplified beam 110 can be a laser beam if the target provides sufficient feedback to the laser system 115 to produce coherent laser light, or if the driving laser system 115 includes suitable optical feedback to form a laser cavity. .

Referring to FIG. 2A, the light source 100 includes a set in an example. A final focus assembly 210 and a beam delivery system 240 between the laser system 115 and the target position 105 are driven. This final focus assembly 210 focuses the amplified beam 110 at the target location 105 in the vacuum vessel 130. The drive laser system 115 produces an amplified beam 110 that is received by the beam delivery system 240. After the amplified beam 110 passes through the beam delivery system 240, it reaches the final focus assembly 210. This final focus assembly 210 focuses the amplified beam 110 and directs the beam 110 to the vacuum vessel 130.

As described below, while the light source 100 is operating, the light is amplified The alignment of the beam 110 can be actively adjusted. In particular, to determine that an uneven temperature distribution exists on a lens holder 212, the main controller 155 controls the final focus assembly 210 and/or light by moving and/or repositioning the guiding elements. A guiding element in the beam transport system 240. Moving and/or repositioning the guiding elements adjusts the position of the magnified beam 110 such that the magnifying beam 110 is aligned to maximize EUV light generation. This guiding element can be any element in the light source 100 that can affect the position and/or orientation of the amplified beam 110.

Beam delivery system 240 includes a guide module 242. This guiding mode Group 242 includes one or more optical components (such as a mirror body) that, when positioned or moved, cause a corresponding change in the position of the magnified beam 110. The main controller 155 controls the optical components of the guide module 242 by, for example, providing a signal to the optical assembly to move or change the position of the assembly. An example of an optical component in the guide module 242 will be discussed below with respect to FIG. The interaction between the main controller 155 and the optical components of the guide module 242 is discussed below with respect to Figures 7 and 8.

The final focus assembly 210 includes a mirror 214, a lens holder 212, final focus lens 218, support frame 220, and positioning actuator 221. The steering mirror 214 receives the beam 110 from the beam delivery system 240 and reflects this beam 110 toward the final focus lens 218, which focuses the beam 110 at the target location 105. Since the interaction between the focused beam 110 and the droplets causes EUV light to be generated, and maintaining proper alignment of the beam 110 can help maintain the focus position at the target position 105, monitoring the position and quality of the beam 110 and responding to the monitoring Repositioning the beam 110 can improve the performance of the light source 100.

Lens holder 212 surrounds lens 218 and lens holder 212 The temperature is proportional to the temperature on the surface of the lens 218. 2B shows a front view of an exemplary embodiment of the lens holder 212 taken along line 2B-2B of FIG. 2A. In the example shown in FIGS. 2A and 2B, lens holder 212 is a thermal shield that extends outwardly from lens 218. Different parts of the lens holder 212 The temperature is measured by temperature sensors 228A, 228B, 228C, and 228D. Temperature sensors 228A, 228B, 228C, and 228D are spaced substantially equidistant from one another along perimeter 234 of lens holder 212. Temperature sensors 228A-228D can be placed on inner surface 237 and/or outer surface 238 of lens holder 212. While the sensors 228A-228D are shown as being placed along the periphery of the lens holder 212, this is not necessarily the case. Sensors 228A-228D can be placed anywhere on inner surface 237 and/or outer surface 238 of lens holder 212.

The temperature measured by any of the sensors 228A~228D is closest to The temperature of a portion of the lens 218 of a particular temperature sensor is proportional. For example, the temperature measured by temperature sensor 228A represents the temperature on portion 235 of lens 218. Likewise, the temperature measured by temperature sensor 228B represents the temperature on portion 236 of lens 218.

Like the beam delivery system 240, the final focus assembly 210 includes an introduction The beam 110 can be adjusted to correct for misaligned optical components. For example, the final focus assembly 210 includes a steering mirror 214. The steering mirror 214 includes a holder 217 having a reflective portion 215 that reflects the amplified beam 110, and moves in one or both of the "X" and "Y" directions in response to receiving a command signal from the main controller 155. The holder 217 and/or the actuator 216 of the reflective portion 215. Thus, the mirror 214 can direct the amplified beam 110 to a particular portion of the final focus lens 218. This can assist in ensuring that the beam 110 is focused at the target location 105. The final focus assembly 210 can also include an actuator that positions the lens 218 in the "X" direction to further adjust the focus position of the beam 110.

The amplified beam 110 passes from the final focus assembly 210 into the vacuum vessel 130. The amplified beam 110 passes through the aperture 140 in the concentrating mirror 135 and The target position 105 travels. The amplified beam 110 interacts with the droplets in the target mixture 114 to produce EUV light. The vacuum vessel 130 can be monitored by an EUV monitoring module 241. The EUV monitoring module 241 can include a light source detector 165 as discussed with respect to FIG. 1A. The output of the EUV monitoring module 241 is provided to the main controller 155 and this output can be used to monitor the amount of EUV light generated. For example, the output of the EUV monitoring module 241 can be used to adjust components in the steering module 242 and/or the steering mirror 214 to maximize the amount of EUV light generated at the target location 105.

Figures 3A and 3B show as a function of time as if by coupling The temperature measured by the four thermocouples on the surface of the final focus mirror. This final focus mirror can be similar to lens holder 212 described above. Thermocouples can be placed on the mirror cover in a manner similar to sensors 228A-228D (Figs. 2A and 2D). In Figures 3A and 3B, time series 302, 304, 306, and 308 each represent a temperature measured by a particular thermocouple over a period of time.

FIG. 3A shows that a relatively unstable amount is generated according to the light source 100. An example of one of the data collected for EUV power, FIG. 3B shows an example of data collected based on the relatively stable (fixed) amount of EUV power generated by source 100. The final focus mirror can be similar to the lens holder 212 shown in Figure 2B.

As shown in the example, the light source 100 is small at a burst rate of 900 Hz. Operating in burst mode. Comparing Figures 3A and 3B, the temperature of the final focus mirror is relatively constant over a period of time when the source 100 produces a stable EUV power (Fig. 3B) when the source 100 produces a relatively unstable EUV power. For example, Figure 3B shows that there will be a temperature deviation of about 1 to 2 degrees Celsius over a period of time, and a temperature deviation of about 2 to 4 degrees Celsius will occur between four thermocouples at a specific time. Poor; even when the light source 100 produces relatively stable EUV power. Conversely, Figure 3A shows the temperature measured by a particular thermocouple over a period of time and the large change in temperature measured by all thermocouples at a particular time. Thus, by adjusting the temperature over a period of time at a plurality of locations on the mirror cover and adjusting the beam until the temperature profile measured on the thermal mask becomes relatively constant in time and/or space, the source The stability and quantity of EUV power generated by 100 can be improved.

4A to 5B, FIG. 4A is the most misaligned beam 110 A side view of the final focus lens assembly 210, while FIG. 4B shows a front view of one of the final focus lenses 218, and the beam 110 is taken along line 4B-4B in FIG. 4A. FIG. 5A is a side view of the final focus lens assembly 210 with the beam 110 aligned normally. Figure 5B shows a front view of one of the final focus lenses 218 taken from line 5B-5B in Figure 5A.

In the example shown in Figures 4A and 4B, the beam 110 is misaligned. And passing through the final focus lens 218 at a location 243 remote from the center 244 of the lens 218. Thus, a portion of the lens near temperature sensor 228A is warmer than other portions of lens 218, and sensor 228A produces a higher temperature reading than sensors 228B, 228C, and 228D. Moreover, since the beam 110 does not pass through the center 244 of the lens 218, the beam 110 will not focus on the target location 105. Therefore, the fine droplets in the target mixture 114 may not be easily converted into plasma, resulting in only some or no EUV light.

Temperature readings from sensors 228A~228D are provided to the master Controller 155. The main controller 155 compares the temperature readings and determines the position of the beam 110, such as relative to the center 244 or in space coordinates. Main controller 155 A signal is provided to the mirror 214 for a signal sufficient to cause the reflective portion 215 to change position to move the beam 110 into the center 244 of the lens 218.

As shown in Figures 5A and 5B, the mirror 214 is at "A" and "B" The direction moves to move the beam 110 to the center 244 of the lens 218. Actuator 221 also moves lens 218 in the "Z" direction to focus beam 110. Due to these adjustments, beam 110 is symmetric on lens 218 and each temperature sensor 228A-228D measures approximately the same temperature. The beam 110 is focused at the target location 105 and illuminates the droplets in the target mixture 114. This fine droplet is converted into a plasma and emits EUV light.

Therefore, compared with the examples of FIGS. 4A and 4B, by using a mirror The 214 positioning beam 110 causes the beam 110 to pass through the center 244 of the lens 218, and the amount of EUV light generated increases. Moreover, the stability of the amount of EUV light can also be improved because by monitoring the alignment of beam 110 with respect to lens 218, beam 110 can be more uniformly focused at target location 105, thereby producing a relatively fixed amount of EUV light.

Referring to Figure 6, an exemplary beam delivery system 600 is placed in a drive mine The injection system 605 and the target position 610. The beam delivery system 600 includes a beam delivery system 615 and a focus assembly 620. This beam delivery system 615 can be used as the beam delivery system 240, and the focus assembly 620 can be used as the final focus assembly 210.

Beam delivery system 615 receives an amplified beam 625 generated by drive laser system 605, redirects and expands the amplified beam 625, and then directs the expanded redirected amplified beam 514 to focus assembly 620. This focus assembly 620 focuses the amplified beam 625 on the target location 610.

Beam delivery system 615 includes optical components, such as changing magnification The mirror bodies 630, 632 and other beam guiding optical elements 634 in the direction of the beam 625. Optical components 630, 632, 634, and 638 can be included in guide module 242 of beam delivery system 240 (Fig. 2A).

Beam delivery system 615 also includes a beam expansion system 640 that The amplified beam 625 is expanded such that the lateral extent of the amplified beam 625 sent by the beam expanding system 640 is greater than the lateral dimension of the amplified beam 625 entering the beam expanding system 640. The beam expanding system 640 can include a curved mirror having a reflective surface of the off-axis segment of the elliptical paraboloid (this mirror can also be referred to as an off-axis parabolic mirror). This beam expanding system 640 can include other optical components that are selected to redirect and expand or collimate the amplified beam 625. A variety of designs for the beam expansion system 640 are discussed in U.S. Patent Application Serial No. 12/638,092, the entire disclosure of which is incorporated herein by reference.

As shown in FIG. 6, the focus assembly 620 includes a mirror body 650 and includes A focusing element includes a converging lens 655 that is assembled and configured to focus the magnified beam 625 reflected from the mirror body 650 to the target position 610. The converging lens 655 can be a converging lens 218, and the mirror body 650 can be a guiding mirror 214 in the example discussed with respect to FIG. 2A.

Therefore, the mirror bodies 630, 632 in the beam delivery system 615, At least one of 638 and beam directing optical element 634 and mirror body 650 in focus assembly 620 can be movable by using a movable base that is actuated by an actuating system that includes control by the master The 155 controls a motor that provides active pointing control of the amplified beam 625 for the target position 610. can The moving mirror body and beam steering optics can be adjusted to maintain the position of the amplified beam 625 on the lens 655 and to magnify the focus of the beam 625 at the target.

Converging lens 655 can be a ball lens to reduce spherical aberration and other optical aberrations that can be produced by the ball lens. The converging lens 655 can be mounted on the chamber wall as a window, can be mounted inside the chamber, or can be mounted outside the chamber. Lens 655 can be movable and thus can be mounted to one or more actuators to provide a mechanism for active focus control during system operation. Accordingly, lens 655 can be moved to collect amplified beam 625 more efficiently and direct this beam 625 to the target position to increase or maximize the amount of EUV produced. The amount and direction of displacement of the lens 655 is determined in accordance with the feedback provided by the temperature sensors 228A-228D described above or the thermal sensor 710 discussed below.

Converging lens 655 has a diameter that is large enough to capture a majority of the amplified beam 625 and also provides sufficient curvature to focus the amplified beam 625 to the target location. In some embodiments, the condensing lens 655 can have a numerical aperture of at least 0.25. In some cases, the condensing lens 655 is made of ZnSe, which is a material that can be used in infrared applications. ZnSe has a transmission range covering 0.6 to 20 μm and can be used for high power beams generated from high power amplifiers. ZnSe has a low heat absorption in the red end (especially the infrared end) of the electromagnetic spectrum. Other materials that can be used to collect lenses include, but are not limited to, gallium arsenide (GaAs) and diamonds. Additionally, the converging lens 655 can include an anti-reflective coating and can transmit an amplified beam 625 of at least 95% of the wavelength of the amplified beam 625.

Focus assembly 620 may include a metrology system 660 that captures light 665 reflected from lens 655. The captured light can be used to analyze the amplified beam 625 and characteristics of the light from the guided laser 175, for example, to determine the position of the amplified beam 625 and to monitor the change in the focal length of the amplified beam 625.

Beam delivery system 600 can also include an alignment laser 670, which is Positioning of one or more of the components used to align with the beam delivery system 600 (such as the mirror bodies 630, 632, the beam guiding optical element 634, the components within the beam expanding system 640, and the lens front mirror body 650) when deployed And angle or position. This alignment laser 670 can be a diode laser that operates in the visible spectrum to assist in visual alignment of the components.

The beam delivery system 600 can also include a test cartridge such as a camera At 675, it monitors the beam reflected from the droplets in the target mixture 114 at the target location 610 that is reflected from the surface prior to driving the laser system 605 to form a diagnostic beam 680 that can be detected at the detection device 675. . Detection device 675 can be coupled to main controller 155.

Referring to Figure 7, it is shown that the magnifying beam is aligned in the EUV source (or A block diagram of a sample system 700 of a moving laser. The system 700 includes a thermal sensor 710 in communication with a monitored component 720 and a controller 730. This controller 730 is also in communication with the actuation system 740. This actuation system 740 is coupled to and in communication with a guiding element 750.

By monitoring the temperature of the monitored component 720, it is used in system 700. System 700 can cause a drive laser (not shown) to be aligned. Temperature is provided to controller 730, and controller 730 provides a signal 731 sufficient for reorienting guide beam 750 to drive the laser beam to actuation system 740 until the temperature of monitored element 720 is substantially uniform. The driven laser beam can be aligned when the temperature of the monitored component 720 is substantially fixed in time and/or space. Thus, system 700 can be viewed as providing active alignment that drives a laser beam.

The thermal sensor 710 can be any type of sensor that feels When the detector is placed in, in contact with, or in proximity to the monitored component 720, a temperature index of the monitored component 720 is generated. For example, the thermal sensor 710 can be one or more of a thermocouple, a fiber based thermal sensor, or a thermal resistor. The thermal sensor 710 can include more than one thermal sensor, and the plurality of thermal sensors can all be of the same type, or they can be a collection of a plurality of different types of thermal sensors.

The thermal sensor 710 includes a sensing mechanism 712, an input/output (I/O) interface 716, and a power module 718. Sensing mechanism 712 is an active or passive component capable of sensing thermal energy and generating a signal or other indicator indicative of the amount of thermal energy sensed. The I/O interface 716 allows signals or other indicators of the sensed thermal energy to be taken and/or removed from the thermal sensor 710. The I/O interface 716 also allows a user of the system 700 to communicate with the thermal sensor 710 via, for example, a remote computer to access signals generated by the sensing mechanism 712. The thermal sensor 710 can also include a coupling 714 that connects the thermal sensor 710 to one of the surfaces or other portions of the monitored component 720. Coupling 714 can be a mechanical coupling that physically couples thermal sensor 710 to monitored component 720. This coupling 714 can be an element that holds the thermal sensor 710 close to the monitored component 720 but does not physically connect the thermal sensor 710 to the monitored component 720.

The thermal sensor 710 measures the temperature of a portion of the monitored component 720 degree. The monitored component 720 can be any thermal conduction component in the vicinity of the high power optical component 722. For example, the monitored component 720 is a physical component in the vicinity of the high power optical component 722 that transmits or reflects the laser beam through reflection or refraction. Interaction. This high power optical component 722 can be any component that interacts with the driven laser beam through reflection or refraction. For example, high power optical component 722 can be an optical component that is exposed to a large amount of laser power, such as a final focus lens (such as lens 218), a window on the power amplifier (such as input windows 189 and 193 and/or an output window). 185, 190, and 194), a steering mirror (such as guide mirror 214) in the final focus lens assembly, a mirror body downstream of the final focus lens, and/or a spatial filter aperture (such as aperture 197). More than one high power optical component 722 can be monitored simultaneously.

If the temperature of the monitored component 720 is proportional to the temperature of the component 722 The monitored component 720 can be considered to be in the vicinity of the component 722, or affected by it. For example, the monitored component 720 can be an element that holds, supports, or protects such components 722. For example, the monitored component 720 can be a thermal mask surrounding the final focus lens, a mirror body that holds the lens body on one or more sides of the lens body, or a holder that holds a space filter. This monitored component 720 can be in physical contact with the component 722, but this need not be the case, as the monitored component 720 and component 722 can be physically separated from one another.

Thermal sensor 710 measures the monitored component 720 at the monitored component Temperature on one or more locations. This thermal sensor 710 provides a signal to the controller 730 indicating the temperature at one or more locations. In some embodiments, the thermal sensor 710 measures the temperature of the monitored component 720 for a period of time and provides a time series of temperature measurements to the controller 730. This controller 730 analyzes the temperature measurement results to determine if the drive laser beam is properly aligned. Based on the results of this analysis, controller 730 can provide a signal 731 that is sufficient to correct actuation of the laser beam by actuation system 740.

The controller 730 includes an electronic processor 732 and an electronic storage device. 734, and an I/O interface 736. The electronic storage 734 stores instructions and/or a computer program that, when executed, causes the electronic processor 732 to perform some actions. For example, the processor 732 can receive signals from the thermal sensor 710 and analyze the signals to determine that the temperature distribution on the monitored component 720 is spatially and/or temporally non-uniform, and thus the laser beam is driven alignment. An input/output (I/O) interface 736 can be visible or audibly present on the display to the data analyzed by the processor 732. The I/O interface 736 can accept commands from an input device (eg, an operator actuated by an operator of the system 700 or an automated program) to assemble the thermal sensor 710, the actuation system 740, or The data or computer program instructions stored in the electronic storage 734 are updated.

Controller 730 provides sufficient steering system 740 to adjust the guide element A signal 731 at the location of the member 750 is applied to the actuation system 740. This signal may include, for example, a coordinate for a new position of the guiding element 750 or a physical distance to move the guiding element 750 in one or more directions. This signal is in a form that can be accepted and processed by the actuation system 740, and the signal can be transmitted to the actuation system 740 over a wired or wireless connection.

The actuation system 740 includes an actuator 742, a coupling member 744, and an I/O interface 746. The actuation mechanism 742 can be, for example, a motor, a piezoelectric element, a drive lever, or any other element that causes movement in another item. The actuation system also includes a coupling that allows the actuation mechanism 742 to be attached to an external component such that the external component can be moved by the actuation mechanism 742. The coupling member 744 can be a mechanical coupling member in physical contact with the external component, or the coupling member 744 can be non-contact (such as a magnetic coupling) Combined). This I/O interface 746 allows an operator of the system 700 or an automated program to interact with the actuation system 740. This I/O interface 746 can receive a signal from the operator, rather than from the controller 730, sufficient to cause the actuation mechanism 742 to move one of the guiding elements 750.

The guiding member 750 is in contact with the actuating mechanism 742, and the guiding member 750 moves in response to action from actuation mechanism 742. For example, the guide member 750 can be a platform that moves a portion of the platform when a piezoelectric element in the actuation mechanism 742 that is in contact with the platform expands. This guiding element 750 includes an active area 752 that interacts with the driving laser beam. Movement of the guide member 750 causes a corresponding movement of the active region 752, and the change in position of the active region repositions the beam. For example, the active area 752 can be a mirror that reflects the beam, and positioning the mirror can change the direction of beam reflection.

Referring to Figure 8, for adjusting an amplified beam relative to an optical component An example program 800 of the location is displayed. This process 800 can be performed on an amplified beam of light in an EUV source, such as the amplified beam 110 of the source 100 shown in FIG. 1A. The program 800 can be performed by one or more electronic processors included in one of the electronic components that control the positioning of the elements that direct the amplified beam, such as included in the controller 730 described with respect to FIG. Electronic processor 732.

A first temperature profile is taken (step 810). The first temperature The distribution represents the temperature of the component adjacent to a first optical component. This first optical element is arranged to receive the amplified beam 110. The component is adjacent to or adjacent to the first optical component when the temperature on the component is proportional to or affected by the temperature of the first optical component. Therefore, measuring component temperature provides optics An indicator of the temperature of the component, thereby allowing the temperature of the optical component to be measured indirectly. The component and the optical element may be in physical contact with one another, or the component and the optical element may be sufficiently close to each other such that heating of the optical element also heats the component.

The optical element is by reflecting the beam 110, absorbing the beam 110, and/or Or the beam 110 is transmitted to receive the amplified beam 110. This optical element can be any optical component in an EUV light source. The optical element can be, for example, a high power optical element such as a final focus lens, an output window on a power amplifier, a final focus rotating mirror, or a spatial filter aperture. This component in the vicinity of the optical element can, for example, hold or support the optical component.

The first temperature distribution can be representative of the component on or near the component A set of values measured by one or more temperature sensors. Since the temperature of the component is related to the temperature of the optical component, the first temperature profile provides an approximation of the temperature of the optical component. This first temperature profile can be a set of values representing the temperature of a particular portion of the component over a period of time. In some embodiments, the first temperature profile can be a set of values representing a plurality of different portions of the component over a period of time or at a particular temperature.

The first temperature distribution taken is analyzed to determine a temperature Amount (step 820). The temperature metric can be a numerical figure of merit compared to a baseline value. The temperature metric can be any suitable mathematical expression associated with temperature distribution details on or adjacent to one of the components of the optical component. For example, and as will be discussed further below, the temperature metric can be a measure of the spatial symmetry of the temperature distribution, such as a standard deviation or square of the temperature measured at different locations on adjacent optical elements. difference. This temperature metric can be a value, such as a change or rate of change in temperature change, determined from a set of values representing the temperature of one or more of the sensors 228A-228D over a period of time.

As mentioned above, the amount of temperature change on the optical element can be indicated by amplification Beam 110 is misaligned or has poor quality. Therefore, analyzing the first temperature profile to determine if the temperatures are relatively consistent provides an indication of beam alignment and beam quality. For example, the first temperature distribution can be analyzed by determining the degree of spatial symmetry. The degree of spatial symmetry can be calculated, for example, by taking temperature measurements taken from four temperature sensors 228A-228D (Fig. 2A) that are substantially evenly spaced along one surface of lens holder 212 (Fig. 2A). . At a particular time, the measurements from temperature sensors 228A-228D each provide a temperature index for a corresponding portion of final focus lens 218. If the amplified beam 110 is eccentrically passed through the lens 218 as shown in FIG. 4B, the values of the temperature readings from the temperature sensors 228A and 228C are greater than the values from the temperature readings of the temperature sensors 228B and 228D. The difference between the temperature readings of the sensors 228A-228D at a particular time may indicate that the beam 110 is not at the center of the lens 218.

The above example relates to the fact that the beam 110 is not in the lens. 218 central situation. In another example, if the beam 110 has an uneven intensity distribution, the sensors 228A-228D are each measured and generate a different temperature, and the highest temperature is from the sensor closest to the beam 110 having the highest intensity. . Thus, by comparing the temperature values from each of the sensors 228A-228D, the beam 110 can be monitored to determine if there is a spatial non-uniformity in the intensity. If the temperature values from sensors 228A-228D are different, then beam 110 can be determined to have a spatial non-uniformity. Shape of intensity distribution (The amount of intensity as a function of spatial position) can be approximated by ordering the temperature values provided by sensors 228A-228D. The severity of the intensity non-uniformity can be determined by calculating the variance or standard deviation of the temperature measured by the sensors 228A-228D.

In another example, the first temperature distribution can represent one or more senses A set of values for the temperature of the detectors 228A-228D over a period of time. In this example, the first temperature profile can be analyzed by calculating a variance or standard deviation of a time series of temperature values measured by any of the sensors 228A-228D. Under optimal or acceptable operating conditions, the amplified beam 110 is aligned at the target location 105 for focusing, and the beam 110 does not change position relative to one of the optical elements that interact with the beam 110. If the beam 110 changes position relative to the optical element over a period of time, or if the beam profile of the beam 110 changes over time, the intensity distribution across the optical element will also change. Thus, when the beam 110 is misaligned, the temperature measured by each of the sensors 228A-228D also changes. Analyzing the rate of change of the first temperature profile to determine the variance and/or time of the distribution provides an indication of whether the position or profile of the beam 110 has changed.

The temperature metric determined in step 820 is compared to a baseline temperature metric (step 830). This baseline temperature metric can be one of a metric determined when the light source is operated in an acceptable or optimal manner. The determined temperature metric can be compared to the baseline temperature metric by, for example, subtracting the determined temperature metric from the baseline temperature metric to determine the difference between the two. This difference can be compared to a threshold to determine if the amplified beam 110 is misaligned or will benefit from an adjustment in another condition. E.g, A temperature change greater than 2 degrees Celsius measured by a particular temperature sensor indicates that the amplified beam 110 is misaligned.

The amplified beam 110 is adjusted based on the result of the comparison (step 840). For example, if the temperature measured by sensor 228A increases by 4 ° C for a period of time and the temperature measured by sensor 228 C decreases by 4 ° C for the same period of time, then beam 110 is determined to have been determined Move to the lens 218 closer to a portion of the sensor 228A. An adjustment to move the reflective portion 215 in the "X" direction to move the beam 110 toward the sensor 228C in a corresponding direction is determined. This adjustment can be a signal generated by the main controller 155. This signal may include information specifying the amount of movement to be induced by the actuator 216. When the actuator 216 receives and processes this signal, the actuator 216 moves the reflective portion 215 such that the beam 110 moves to a lower position on the lens 218.

There are other examples that fall within the scope of the attached patent application.

100‧‧‧Light source

105‧‧‧ Target location

110‧‧‧Amplified beam

114‧‧‧Target mixture

115‧‧‧Laser system

127‧‧‧ target supply device

130‧‧‧Case/vacuum container

135‧‧‧ concentrator

140‧‧‧ aperture

155‧‧‧Master controller

210‧‧‧Final Focus Assembly / Final Focus Lens Assembly

212‧‧‧Lens Holder

214‧‧‧Guide mirror

215‧‧‧reflection

216, 221‧‧ ‧ actuator

217‧‧‧Retainer

218‧‧‧ final focus lens

220‧‧‧Support frame

228A, 228D‧‧‧ Temperature Sensor

240‧‧‧Light transmission system

241‧‧‧EUV monitoring module

242‧‧‧guide module

Claims (25)

A method of adjusting a position of an amplified beam relative to a first optical element in an extreme ultraviolet (EUV) light source, the method comprising: taking a first temperature indicative of a temperature adjacent to the first optical element and a component thereof Distributing, the first optical component is configured to receive the amplified beam; analyzing the first temperature profile taken to determine a temperature metric associated with the component; comparing the determined temperature metric to a baseline temperature metric And determining, according to the comparison result, the position of the amplified beam relative to one of the first optical elements required to be adjusted. The method of claim 1, further comprising generating an indicator indicative of an adjustment determined for the location of the amplified beam. The method of claim 2, wherein: the indicator includes an input for an actuator coupled to a second optical component; the second optical component includes an active region disposed to receive the amplified beam; and The inputs of the actuator are sufficient to cause the actuator to move the active area in at least one direction. The method of claim 3, further comprising providing the input to the actuator. The method of claim 4, further comprising: after providing the input to the actuator, accessing the first optical a second temperature distribution of the component of the component; analyzing the second temperature profile to determine the temperature metric; and comparing the temperature metric to one or more of the first temperature profile or the baseline temperature metric. The method of claim 3, wherein the active area of the second optical element comprises a mirror body having a reflective portion that receives the amplified light beam, and the reflective portion changes the magnification relative to the first optical element while moving The position of the beam. The method of claim 3, wherein the indicator further comprises an input for coupling to a second actuator of a third optical component in the EUV source, the inputs to the second actuator being sufficient for The second actuator moves the third optical element in at least one direction. The method of claim 1, wherein the first temperature profile comprises a temperature adjacent a portion of the component of the first optical component, the temperature of the portion being measured at least two different times. The method of claim 1, wherein the first temperature profile comprises a temperature of a plurality of portions of the component adjacent the first optical component. The method of claim 9, wherein the temperature of each of the plurality of portions is measured at least two different times. The method of claim 10, wherein the first temperature profile comprises data indicative of temperature measurements received from a thermal sensor, the thermal sensors being mechanically coupled to the component adjacent the first optical component. The method of claim 1, wherein the first optical component comprises a converging lens through which the magnifying beam passes, and the component adjacent to the converging lens comprises A mirror cover. The method of claim 1, wherein the first temperature profile comprises a plurality of temperatures measured by the component at a plurality of times, and the temperature metric comprises one of the plurality of temperatures, an average of the plurality of temperatures, or One or more of a rate of change between at least two of the temperatures. The method of claim 1, wherein the first temperature profile comprises a plurality of temperatures measured at different locations on the component at a particular time, and the temperature metric comprises a spatial variance of the plurality of temperatures. The method of claim 13, wherein the first temperature profile further comprises a plurality of temperatures measured at different locations on the component adjacent the first optical component. The method of claim 15, wherein the temperature metric further comprises a spatial variance of the plurality of temperatures measured at different locations on the component adjacent the first optical component. The method of claim 1, wherein the temperature metric comprises a value indicative of a temporal change in a measured temperature of the component adjacent the first optical component, and comparing the temperature metric to a baseline temperature metric comprises including The value is compared to a threshold. A system comprising: a thermal sensor configured to: mechanically couple to a component adjacent a first optical component that receives an amplified beam of one of an extreme ultraviolet (EUV) light source; measure a temperature of the component And an indicator that produces the measured temperature; and A controller comprising one or more electronic processors coupled to a non-transitory computer readable medium, the computer readable medium storing software comprising instructions executable by the one or more electronic processors, the instructions being When executed, the one or more electronic processors perform the following actions: receiving an index generated by the measured temperature; and generating an output signal according to the measured value of the measured temperature, the output signal is sufficient The actuator is moved to receive a second optical element of the amplified beam and a position of the amplified beam is adjusted relative to the first optical element. The system of claim 18, wherein the instructions further comprise instructions to provide the output signal to the actuator, and wherein the actuator is coupled to the second optical component. The system of claim 18, wherein: the first optical component is such that the amplified beam passes through a lens; the component adjacent to the lens is a mirror cover adjacent to the lens; and the thermal sensor sets It is fitted to the mirror cover. The system of claim 18, wherein the thermal sensors comprise one or more of a thermocouple, a thermal resistor, or a fiber-based thermal sensor. The system of claim 18, wherein the instructions further comprise instructions that, when executed, cause the controller to: take a first temperature profile based on the thermal sensor from the thermal sensor An index of the measured temperature of the component; analyzing the temperature profile taken to determine a temperature metric associated with the component; The determined temperature metric is compared to a baseline temperature profile; and an adjustment required to determine one of the parameters of the amplified beam is determined based on the comparison. The system of claim 18, wherein the first optical component comprises one or more of a power amplifier output window, a final focus rotating mirror, or a spatial filter aperture. The system of claim 18, wherein the thermal sensor comprises a plurality of thermal sensors, the first optical component comprising one or more optical components downstream of a lens that focuses one of the amplified beams, and each of the one or more The optical elements are coupled to a thermal sensor. A system comprising: a first optical component that receives an amplified beam of one of an extreme ultraviolet (EUV) light source; an element adjacent to and separate from the first optical component; coupled to the first optical component A thermal system of components, the thermal system comprising: one or more temperature sensors each associated with a different portion of the component, the one or more temperature sensors being configured to produce one of the components An index of a measured temperature of the associated portion; an actuating system coupled to a second optical element that causes a corresponding movement of the amplified beam when the second optical element moves; and a control system that is coupled One of the output of the thermal system and one or more inputs of the actuation system, and is configured to measure temperature according to the quantity The indicator produced by the degree produces an output signal for input to the actuation system that is sufficient for the actuator to move the second optical element and adjust one of the positions of the amplified beam relative to the first optical element.